The detection of weak magnetic fields with high spatial resolution is an important problem in diverse areas ranging from fundamental physics and material science to data storage and biomedical science.
Over the past few decades, a wide variety of magnetic sensors have been developed using approaches that include, but are not limited to, SQUIDs (superconducting quantum interference devices), atomic vapor-based magnetometers, and magnetic resonance force microscopy. Even state-of-the-art systems have great difficulty, however, in detecting weak magnetic fields in small regions of space and under ambient environmental conditions such as temperature.
Magnetometers based on solid state electronic spin systems have been proposed in co-pending PCT application No. PCT/US08/85424, filed concurrently herewith on Dec. 3, 2008, the contents of which are incorporated herein by reference. One of the advantages of such solid state spin systems is that they have the potential to achieve a very high density of sensing spins, which in turn translates into an improvement of sensitivity to the average magnetic field over the magnetometer volume.
At very high spin densities, however, couplings among the electronic spins may no longer be ignored. The electronic spins may lose spin coherence by interacting with mutually resonant photon frequencies, causing the electronic spins to flip by energy transfer, through mutual spin-orbit coupling, and through photon emission.
It is desirable to provide methods and systems for increasing the sensitivity of magnetometers that are based on solid state electronic spin systems. At high spin densities, in particular, methods and systems for decoupling electronic spins from each other and from the local environment are needed.